While 3D and stereoscopic technologies are becoming more and more ubiquitous, content creation is limited to a non-critical mass of stereo movies and video games. The stereoscopic display of HTML pages onto stereo-enabled TV screens (3DTVs) and computer monitors, to produce a 3D-like visual reality from 2D environments, and in particular, from 2D web pages, has not caught on.
A stereoscopic image presents the left and right eyes of the viewer with different perspective viewpoints, just as the viewer sees the visual world. From these two slightly different views, the eye-brain synthesizes an image of the world with stereoscopic depth. You see a single—not double—image, since the two are fused by the mind into one which is greater than the sum of the two. So called 3D computer-generated images produced from a three-dimensional source file require the computation of an image from a single perspective point of view or location in space. A stereoscopic image differs only in that the image must be generated from two locations. Hence, the terms “3-D” or “three-dimensional”, particularly as used in the field of computer graphics, is used to refer to a “realistic”-looking image which may be appreciated with one eye. The usual so-called 3-D computer image loses nothing when you close one eye. A true stereoscopic image on the other hand loses its intended essence of expression when viewed with one rather than two eyes. The creation of stereoscopic images, and in webpages, in particular, is the subject matter of this application.
There are a number of known techniques for converting images (either 2D images or actual 3D images designed for single perspective point of view) to stereoscopic images. Few examples include: 1) Manual shifting of objects in horizontal axis using digital image processing software like PhotoShop, 2) The DBIR method (Depth-Based Image Rendering) where apart from 2D images an extra depth map is used to calculate the shifting, 3) Semi-automatic and user-guided variations of the above methods where designers try their best to mark depths in a perceptually consistent way, 4) Multiple 2D shoots os the same scene with various focal distances in order to find a correlation between the stereoscopic depth and the amount of blur over the surfaces, 5) Techniques specific to captured content and not computer synthesized like the use of special hardware to measure the depth using bounced infra-red light off of objects read in by a common camera, 6) Stereo Rigs used in cinematography and which is not useful at all in the web content creation.
Computing a stereoscopic image involves drawing two monocular viewpoints from different positions and creating dual 2D images. It is also possible to generate a stereoscopic image from a true 3D image.
When a computer browser retrieves a webpage, it does so with the intent of decoding the HTML code to generate an image. This image is traditionally 2D, but if the page is designed especially for viewing on a 3D monitor, the display of the content will appear in 3D. Alternatively, if the website content is normal 2D but the monitor has the hardware and/or software capability to convert an inbound 2D image of a website page, for example, to a 3D single perspective image, then it does just that.
Conventional techniques for displaying content stereoscopically (or “in stereo”, for short) employ various known techniques, such as creation of anaglyph images from 2D content. That is filtering the left and right images using chromatically different color filters, —where the two filters should have contrasting colors based on the Trichromacy Theory—and superimposing them into one image to be seen by anaglyph glasses.
Another approach for stereo content creation is to employ complex algorithms that analyze a web page—as a sequence of images—using complex graphics processing units (GPUs) that run performance limiting data crunching solutions that operate to generate 3D content from 2D images. To achieve this, web content is analyzed to identify objects. These objects are then manipulated to appear as 3D viewable pages on a 3D monitor or television, using the appropriate 3D glasses.
Another recent approach that has been proposed is the introduction of features or function calls into the HTML code, by web content creators using extensions of Cascade Style Sheets (CSS), and in particular CSS3. In this regard, CSS3 introduces the ability of website creators to dictate a priori how a website shall appear when projected onto a 3D viewable area or screen. This method is designer-driven, requires a website remake and cannot by applied to the existing web without extra costs.
What are needed are new approaches by which to generate stereoscopic images of 2D web pages.